City Clerk Susana Mendoza said Tuesday she’s investigating whether gang signs are part of the winning design for Chicago’s next city sticker, just days before the decals are scheduled to be printed.

The sticker, meant to honor city firefighters, paramedics and police, was designed by a 15-year-old boy who attends a school for troubled youth.

The artwork shows four hands lifted skyward toward symbols of the three professions — above a heart containing a carefully rendered city skyline against the city flag.

A blogger who writes about police issues identified the position of those hands as symbols often flashed by members of a notorious Chicago street gang. Concerned citizens began calling the clerk’s office Tuesday after those allegations hit the web, the clerk’s office said.

“Every artist has a back story and oftentimes artwork is controversial,” Mendoza said in a statement. “However, the artwork on Chicago’s city stickers should not be controversial.

“In a design that is meant to honor the city’s first responders, I am very sensitive to this issue. I grew up in a neighborhood filled with crime and gang violence and I come from a law-enforcement family,” Mendoza added.

Exactly what’s on the city stickers is a touchy subject, in part because they will be the first to carry the names of Mendoza and Mayor Rahm Emanuel.

Jody Weis, a former police superintendent who is now president of the Chicago Crime Commission that puts out a handbook on city gangs, said he initially saw the imagery on a Blackberry and didn't think it looked like a gang sign.

But a short time later, when he blew up the picture on an iPad, he could see it much clearer and he changed his mind.

“It’s very, very close to a gang sign,’’ Weis told the Tribune when reached by phone Tuesday night. “It’s not exactly, but it’s very close,’’ Weis said. “It’s too close to be a coincidence.’’

Weis explained that the left and right hands shown in the artwork are the same.

“Every finger configuration is identical,’’ he said.

Weis said he believes authorities should take a closer look at the artwork.

“I don’t know what was in the boy’s heart, but somebody needs to find that out,’’ Weis said.

“For a city sticker, it would spark controversy,’’ Weis said. “You don’t want that kind of controversy on a city sticker.’’

The new city sticker was picked after a round of judging and another round of voting. In the first round, judges invited by the clerk’s office crowd into City Council chambers and rank their favorites from among hundreds of designs submitted by high school students.

The top 10 then were posted at suntimes.com, and Mendoza said more than 18,000 votes were cast.

The winning design was announced last week at a news conference. The teen said his mother and his school, Lawrence Hall Youth Services, were helping him improve his academic performance. He said he was honoring firefighters because they rescued him when he was 4 and had lit his clothes on fire with a candle.